POWER SUPPLY CONTROL METHOD AND POWER SUPPLY CONTROL DEVICE

A power supply control device (100) includes a high-power battery (12), a low-power battery (15), a relay (13) that electrically connects the high-power battery (12) and the low-power battery (15), a power supply switch (11), and a controller (10) that controls an on/off state of the relay (13). When a power supply state is a state in which power is supplied from the high-power battery (12) to the low-power battery (15) with the relay (13) therebetween, if the controller (10) receives a first signal, the controller (10) switches the relay (13) from an on state to an off state, and then inhibits the relay (13) from switching from the off state to the on state.